1. Field of the Invention
The present invention relates to an object conveying device that mounts a conveyed object to a predetermined position while aligning it and, particularly, to an object conveying device that mounts a light-weight conveyed object to a predetermined position.
2. Description of the Related Art
An optical disk is generally manufactured by producing a master disk where recording information, a file structure, and disk specifications, such as format specifications, are recorded on a glass substrate and duplicating the master disk into a plastic substrate.
In general, duplication of the master disk into a plastic substrate is performed by an injection molding method where a definite amount of a plastic material is injected into a molding die having a plastic substrate shape, and cooled and solidified as it is. For the duplication of pit shapes on an information recording surface, a stamper is used that has replicated the pit shapes on the information recording surface of a master disk by electroplating the information recording surface. When the above-described injection molding is to be performed, the stamper is mounted inside the molding die with the surface on which the pit-shapes have been replicated faced toward the inside of the molding die. By performing injection molding in this state, an optical disk having desired pit shapes is produced.
The stamper used in this duplication process of the optical disk is stored for each kind of produced optical disk, and when the plastic substrate is to be duplicated, the stamper is replaced every time the kind of optical disk to be duplicated changes. Generally, the mounting of the stamper at a stamper replacement is performed by using a stamper mounting device, and the mounting of the stamper by the stamper mounting device is performed while aligning the stamper with a predetermined position of the molding die.
The mounting of the stamper is performed by pressing the head portion of the stamper mounting device holding the stamper against the inside of the molding die. In this case, the alignment of the stamper is performed by a reference pin for alignment provided at the head portion of the stamper mounting device being guidedly inserted into a recess of the molding die, which is a reference pin receiving hole provided inside the molding die.
However, conventional stamper mounting devices are insufficient in the flexibility of the head portion to position variations. As a result, when the reference pin provided at the head portion is guided into the recess provided inside the molding die, an excessively large force is applied to the contact portion between the reference pin and the molding die recess. This raises a problem that the reference pin and/or the molding die recess may be deformed and/or damaged.
Also, at an alignment of the stamper, when the stamper holding surface of the head portion tilts with respect to the stamper mounting surface of the molding die, the stamper held to the head portion is pressed against this stamper mounting surface in a state tilting with respect to the stamper mounting surface of the molding die. This creates a problem that the stamper may be deformed and/or damaged.
Accordingly, it is an object of the present invention to provide an object conveying device capable of mounting a conveyed object, such as a stamper, to a predetermined position while aligning it without deforming or damaging a reference pin and/or a molding die.
It is another object of the present invention to provide an object conveying device capable of mounting a conveyed object, such as a stamper, to a predetermined position while aligning it and without deforming or damaging it.
In order to achieve the above-described object, the present invention, in a first aspect, provides an object conveying device that mounts a conveyed object to a predetermined position while aligning it. This object conveying device comprises a support portion that is provided with power to move the conveyed object; a first elastic member held to the support portion; an aligning bearing wherein one of an inner ring and an outer ring is held to the first elastic member; and a conveyed object holding mechanism that holds the conveyed object, the conveyed object holding mechanism being held to one end of the ring that is not held to the first elastic member out of the inner and outer rings of the aligning bearing.
Herein, the first elastic member and the aligning bearing provide the conveyed object holding mechanism with flexibility to position variations and angle variations and, thereby, corrects positional deviations and tilting of the conveyed object when aligned.
Also, the present invention, in a second aspect, provides an object conveying device that mounts a conveyed object to a predetermined position while aligning it. This object conveying device comprises a support portion that is provided with power to convey the conveyed object; a first elastic member held to the support portion; an aligning bearing wherein one of an inner ring and an outer ring is held to the first elastic member; a common plate held to one end of the ring that is not held to the first elastic member out of the inner and outer rings of the aligning bearing; a second elastic member held by the common plate; a third elastic member held by the common plate; a tray held by the third elastic member, the tray holding the outer peripheral portion of the conveyed object; a conveyed object adsorbed block held by the second elastic member, the conveyed object adsorbing block holding the inner peripheral portion of the conveyed object at a position projecting in the direction of the conveyed object over the conveyed object holding surface of the tray; a fourth elastic member held by the conveyed object adsorbing block; a center guide held by the fourth elastic member, the center guide positioning the conveyed object with respect to the conveyed object absorbing block; and a reference pin held by the center guide.
Herein, by holding the outer periphery portion of the conveyed object by the tray and holding the inner peripheral portion thereof at a position projecting in the direction of the conveyed object over the conveyed object holding surface of the tray, the conveyed object is held with the inner peripheral portion thereof projected further outward than the outer peripheral portion thereof, and the first elastic member and the aligning bearing provide the conveyed object holding mechanism and the tray with flexibility to position variations and angle variations, thereby correcting positional deviations and tilting of the conveyed object when aligned.
In the object conveying device according to the present invention, it is preferable that the elastic force of the first elastic member be lower than that of the fourth elastic member, and that the elastic force of the fourth elastic member be lower than that of the second elastic member.
Also, in the object conveying device according to the present invention, preferably, the conveyed object adsorbing block holds the inner peripheral portion of the conveyed object at a position projecting in the direction of the conveyed object over the conveyed object holding surface of the tray in the range of 0.8 mm to 1.3 mm.
Furthermore, in the object conveying device according to the present invention, preferably, the conveyed object adsorbing block holds the inner peripheral portion of the conveyed object at a position projecting in the direction of the conveyed object over the conveyed object holding surface of the tray in the range of 1.0 mm to 1.1 mm.
Moreover, the object conveying device according to the present invention preferably has a fifth elastic member that inhibits the common plate from hanging down. Also, in the object conveying device according to the present invention, the fifth elastic member is preferably supported by the support portion, and the fifth elastic member holds the lower portion of the common plate.
Furthermore, in the object conveying device according to the present invention, preferably, the conveyed object is a stamper used for forming pits on an optical disk substrate.